Ring plate valve for piston compressors

ABSTRACT

A ring plate valve for piston compressors includes several individual plastic ring plates ( 3 ) as closing organs, which are concentrically arranged in relation to each other between valve seat ( 1 ) and catcher ( 2 ). The diameter of individual steel spiral springs, that are distributed on the circumference for the purpose of supplying the ring plates ( 3 ) with spring force, is essentially equally large as the width of the ring plates ( 3 ), thereby allowing for the realization of a small spring length. On the side of the catcher, the spiral springs ( 4 ) are supported and guided inside individual spring cups ( 7 ), preferably of abrasion-resistant plastic.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to a self-acting ring plate valve for piston compressors including several individual plastic ring plates as closing organs that are concentrically arranged in relation to each other between a valve seat and catcher and that are loaded from the direction of circumferential fixed links of the catcher vis-à-vis the valve seat by way of individual steel spiral springs.

[0003] 2. The Prior Art

[0004] Valves of this type have been known in the art for a long time (for example, refer to EP-345 245 B or U.S. Pat. No. 3 536 094 A); using special flow-enhanced flow cross sections, they allow, at predetermined ring widths, for an essential reduction of the ventilation losses in comparison to conventionally known constructions (flat steel plate valves or sheet steel ring valves). Assigning springs individually to individual ring plates, furthermore, advantageously allows for various ways to influence the opening and closing behavior of the valves. In realizations that are known in the art, the ring plates are supplied with spring force either by way of joint power distribution plates that have a minimized number of helical springs with high intensity of force or, however, individually, i.e. in a direct manner, by way of a higher total number of spring cups with a lower intensity of force that are distributed along and become engaged in the circumference of the ring plates.

[0005] In the first instance referred to above, the power distribution plate is the cause for frequent problems with regard to the guiding action of the individual ring plates, because, to fulfill this function, the power distribution plate must either be realized as a special part or guide elements of the catcher must extend through the power distribution plate, causing a considerable portion of the flow cross section area of the power distribution plate to be lost, specifically in order to accommodate these guide elements, which causes the ventilation losses to increase. In the second instance referred to above, although, on the one hand, the individual ring plates can be easily guided along the total lift of the stroke, on the other hand, however, the constructive realization of the catcher is the reason for the problem that only springs with relatively small outside diameters can be accommodated, as the springs would otherwise extend beyond the circumferential fixed links of the catcher and into the flow cross section, preventing them from having a snug fit on the contact surfaces of the end windings, which is a reason for locale-specific overstressing. If the outside diameter of the individual spiral springs is small, a very high number of windings is required for achieving the predetermined spring resistance while, all the while, maintaining the allowable material stress in the presence of a dynamic load; this, once again, is the reason for a high total spring length, specifically due to the fact that the diameters of the spring wire cannot be reduced in whichever way that is desired. But this represents a considerable increase of the overall height fundamentally compromising the applicability in narrow valve nests or reducing the delivery quantity due to the resulting high damage space definition in suction valves.

[0006] The subject-matter of the present invention consists in avoiding the disadvantages of the embodiments known in the art that were referred to at the outset and, in particular, in improving a self-acting ring plate valve of the construction style previously described in such a way that it is possible to securely guide the individually spring-supplied individual ring plates while maintaining ventilation losses at a level that is as low as possible, and while preventing, simultaneously, that the realization of the springs will cause an insubordinate increase of the height and/or of the damage space associated therewith.

Summary of the Invention

[0007] With regard to a ring plate valve of the type referred to at the outset, this objective is achieved, according to the present invention, by providing that the diameters of the spiral springs are essentially equally large as, or minimally smaller than the width of the ring plates at the contact locations of the spiral springs, and by providing that, on the side of the catcher, the spiral springs are supported and guided inside individual spring cups that rest in blind-hole-type recesses of the circumferential fixed links of the catcher and, when the ring plates are in their open state, the spring cups close off to the outside the space that is occupied by the spiral springs, at least for the most part. With large outside spring diameters, it is possible to realize valve springs that have a predefined intensity of force over a given lift of stroke and a smaller height than springs with small outside diameters. In fact, in the latter case, a very high number of windings is required in order to achieve the predetermined spring resistance while, all the while, maintaining the allowable material stress in the presence of a dynamic load; but the high number of windings, in turn, correspondingly increases the overall length of the spring. Due to the fact that, for the purpose of ensuring favorable flow conditions, the width of the individual ring plates corresponds essentially to the width of the respectively assigned fixed links of the catcher, simple nests of springs on the circumferential fixed links of the catcher could, for larger diameters, only provide partial support for the spring ends on the side of the catcher; and this would lead to unmanageable problems with regard to highly dynamic stresses that are normally present in these apparatuses. According to the invention, this problem is prevented with the use of the spring cups referred to earlier, which are located in the blind-hole-type recesses of the circumferential fixed links of the catcher, because the spring cups provide a secure support for the spring ends on the side of the catcher, even with regard to the circumferential fixed links that usually, for reasons of flow, become progressively thinner the larger the distance from the ring plates. In addition, the individual spiral springs are safely guided inside these spring cups and optimally protected against environmental factors such as, for example, hot or aggressive gases that are to be controlled.

[0008] In a particularly preferred embodiment of the invention, it is envisioned that the spring cups are comprised of thermoplastic or duroplastic materials, preferably polyamides, polyphenyl sulfides, polyetherketone, phenolic resins or epoxy resins, that contain filler or reinforcement materials, preferably carbon fibers, graphite, aramide or fluorocarbon polymers in order to increase the abrasion resistance. Relative motions between spiral springs and surfaces that are contacting the spiral springs (ring plate, spring nest floor and essentially cylindrical spring nest side surfaces) can, if the construction is made of steel or materials of similar hardness on both ends, lead to wear and tear and ultimately to an increased risk of fracture. By realizing the spring cups as made of abrasion-resistant and wear-and-tear-reducing plastic materials including special additives, the spiral springs are optimally protected against abrasion on all potential contact surfaces. On the one hand, this applies with regard to the surfaces on the spring cup floor and on the plastic ring plate that are in direct contact with the spiral springs; on the other hand, this applies with respect to the potential contact surfaces between the spring jacket surface and the inside jacket surface of the spring cup, if a rotation of the latter is initiated during the ring plate motion, causing an excursion of the spring ends in the direction of the circumference. Simultaneously, this will protect the catcher, due to the plastic spring cups, from wear and tear in locations of potential micro-motions.

[0009] According to another embodiment of the invention, a ventilation opening can be arranged on the floor of the spring cups that ventilates the space occupied by the spiral springs by way of at least one opening, which is envisioned on the floor of the recesses of the circumferential fixed links of the catcher, and the opening leads to the outside and/or inside circumference of the circumferential fixed links. Very simply, in this way, it can be ensured that, for example, pressure waves in the spring nest initiated by the ring plate dynamics are avoided. Moreover, deposits of oil, dirt etc. penetrating the spring nest can be evacuated via the ventilation path that was previously referred to.

[0010] In the context of the latter example, another embodiment of the invention is particularly advantageous. It provides that, in order to create the openings leading to the outside and inside circumferences of the circumferential fixed links of the catcher, the recesses in the circumferential fixed links of the catcher feature a graduated area in the floor area whose diameter is even larger than the width of the circumferential fixed links at that location. This allows for a very simple manufacture of the necessary ventilation openings, while the spring cups are still able to rest securely on the graduation of the recess on the floor.

[0011] To achieve self-acting centering of the spiral springs, in another embodiment of the invention, the floor of the spring cups can be realized as conical at least in the spring support area, which easily improves the guiding and supporting action of the spiral springs.

[0012] Subsequently, the invention will be described in more detail using the drawings of an in part schematically depicted embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 shows an exploded view of a partial section of a ring plate valve according to the invention, and

[0014]FIG. 2 depicts a partial section of the same valve in its assembled state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] The shown self-acting ring plate valve has three individual plastic ring plates 3 as closing organs that are arranged concentrically in relation to each other between the valve seat 1 and catcher 2 and that are loaded from the direction of the catcher 2 vis-à-vis the valve seat 1 by way of individual steel spiral springs 4 distributed along the circumference. The diameters of the spiral springs 4 are essentially equally large as, or minimally smaller than the width of the ring plates 3 at the contact locations of the spiral springs 4, which allows keeping the total spring length relatively low in the presence of a certain required predefined intensity of force over a given lift of stroke area. On the side of the catcher 2, the spiral springs 4 are supported and guided inside individual spring cups 7 that rest in individual blind-hole-type recesses 5 of the circumferential fixed links 6 of the catcher 2 and, when the ring plates are in their open state (FIG. 2 shows the closed state), the spring cups close off to the outside the space that is occupied by the spiral springs 4, at least for the most part. This also allows for secure and full-surface support of the ends of the spiral springs 4 on the side of the catcher with regard to the circumferential fixed links 6 that, as shown, taper away from the ring plates 3, and the springs themselves are well protected and not exposed to, for example, hot or aggressive gases that are to be controlled.

[0016] The spring cups 7 can be comprised of thermoplastic or duroplastic materials, such as polyamides, polyphenyl sulfides, polyetherketones, phenolic resins or epoxy resins that contain filler or reinforcement materials such as carbon fibers, graphite, aramide or fluorocarbon polymers in order to increase the abrasion resistance and to prevent damage to the springs.

[0017] The spring cups 7 have a ventilation opening 9 arranged on their floor 8 (refer to the sectional depiction of the spring cup 7 in FIG. 2) that ventilates the space occupied by the spiral springs 4 by way of at least one opening 10, which is envisioned on the floor of the recesses 5 of the circumferential fixed links 6 of the catcher 2, and the opening leads here to the outside and/or inside circumference of the circumferential fixed links. The opening 10 consists, in the present context, of a graduated area envisioned on the floor of the recess 5 whose diameter is still at least minimally larger than the width of the circumferential fixed links 6 at that location, which causes the entire blind-hole-type recess 5 to be open in the direction of the respectively inside and outside circumference surfaces of the circumferential fixed links 6 of the catcher.

[0018] The floor 8 of the spring cups 7 is, on the inside, realized as conical, which is not clearly visible due to the smallness of the depiction, in particular for the purpose of the self-acting centering of the spiral springs 4 at least in the area of their support; this allows for the easy positioning of the springs 4, which are continually preloaded, inside the spring cups 7.

[0019] During assembly of the ring plate valve, the spring cups 7 can be simply held inside their assigned recesses 5 of the circumferential fixed links 6 of the catcher by choosing an outside diameter that is slightly larger than the diameter of the recess. In particular, with regard to plastic spring cups, this way, it is very easy to achieve problem-free clamping. Therefore, the spring cups 7 that protect the springs also from harmful environmental factors, as described previously, are able to increase the diameter of the individual spiral spring 4 to a level that is preset with the width of the ring plates 3; simultaneously, it is possible to maintain the tapering of the circumferential fixed links 6 of the catcher 2, that is advantageous in terms fluidity, in the direction of flow and away from the valve seat, while avoiding problems with wear and tear at the contact location of the spiral spring 4 on the side of the catcher. The springs are shielded from the gas-filled chamber, in which high flow speeds are present, and from any direct contact with the transported medium or with any abrasive or contaminating particles carried inside the transported medium. 

1. Self-acting ring plate valve for piston compressors comprised of several individual plastic ring plates (3) as closing organs, which are concentrically arranged in relation to each other between valve seat (1) and catcher (2) and which are loaded from the direction of the circumferential fixed links (6) of the catcher (2) vis-à-vis the valve seat (1) by way of individual steel spiral springs (4) wherein the diameter of the spiral springs (4) is essentially equally large as, or minimally smaller than the width of the ring plates (3) at the contact location of the spiral springs (4), and wherein the spiral springs (4) are supported and guided on the side of the catcher (2) in individual spring cups (7) that rest in blind-hole-type recesses (5) of the circumferential fixed links (6) of the catcher (2), and, when the ring plates (3) are in the open state, the spring cups (7) close off to the outside the space that is occupied by the spiral springs (4), at least for the most part.
 2. Ring plate valve as in claimed in claim 1, wherein the spring cups are comprised of thermoplastic or duroplastic materials, preferably polyamides, polyphenyl sulfides, polyetherketones, phenolic resins or epoxy resins, containing filler and/or reinforcement materials, preferably carbon fibers, graphite, aramide or fluorocarbon polymers in order to increase the abrasion resistance.
 3. Ring plate valve as claimed in claim 1, wherein the spring cups (7) have a ventilation opening (9) arranged on their floor (8) that ventilates the space occupied by the spiral springs (4) by way of at least one opening (10) which is envisioned on the floor of the recesses (5) of the circumferential fixed links (6) of the catcher (2), and said opening leads to the outside and/or inside circumference of the circumferential fixed links (6).
 4. Ring plate valve as claimed in claim 3, wherein the recesses (5) in the circumferential fixed links (6) of the catcher (2) feature a graduated area in the floor area for forming the openings (10) that lead to the outside and inside circumferences of the circumferential fixed links (6) of the catcher (2) and whose diameter is even larger at that location than the width of the circumferential fixed links (6).
 5. Ring plate valve as claimed in claim 1, wherein the floor (8) of the spring cups (7) is realized as conical, at least in the area where the spiral springs (4) are supported, in order to achieve the self-acting centering of the spiral springs (4). 